1. Field of the Invention
The present invention relates to a multi-axis turning center for turning a workpiece with a multi-point turning tool, and a turning method for performing a turning process on a workpiece using such a multi-axis turning center.
2. Description of the Related Art
Japanese laid-open patent publication No. 2002-79401, for example, discloses a multi-axis turning center which is capable of performing a turning process on a workpiece with a multi-point turning tool having a plurality of inserts (tips) mounted thereon. The disclosed multi-axis turning center is a machine tool having a basic structure as a lathe, and has a multi-point tool mounted on a tool holder of a tool post.
Since the disclosed multi-axis turning center is essentially a lathe, the multi-point tool can swing with respect to the tool post. However, the multi-point tool is not movable over a stroke large enough to reach various positions around the workpiece which is supported on the multi-axis turning center.
For performing a turning process, a tool post controller energizes a tool drive motor to turn the multi-point tool about its own axis until a desired insert on the multi-point tool is indexed to the machining position. Then, the insert is securely positioned in place and is applied to machine the workpiece in the turning process.
As described above, the multi-axis turning center which basically has a lathe structure is required to perform an indexing control operation to turn the multi-point tool to index the desired insert. As a result, the overall machine tool needs to be controlled according to a complex control process.
For turning the multi-point tool to index the desired insert, the multi-point tool has to be electrically held in position for the turning process. Consequently, it is difficult to increase the rigidity with which the multi-point tool is supported in the turning process.